Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 3.974.558
Filtrar
1.
Chemosphere ; 262: 128371, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33182123

RESUMO

The environment is affected by agricultural, domestic, and industrial activities that lead to drastic problems such as global warming and wastewater generation. Wastewater pollution is of public concern, making the treatment of persistent pollutants in water and wastewater highly imperative. Several conventional treatment technologies (physicochemical processes, biological degradation, and oxidative processes) have been applied to water and wastewater remediation, but each has numerous limitations. To address this issue, treatment using bimetallic systems has been extensively studied. This study reviews existing research on various synthesis methods for the preparation of bimetallic catalysts and their catalytic application to the treatment of organic (dyes, phenol and its derivatives, and chlorinated organic compounds) and inorganic pollutants (nitrate and hexavalent chromium) from water and wastewater. The reaction mechanisms, removal efficiencies, operating conditions, and research progress are also presented. The results reveal that Fe-based bimetallic catalysts are one of the most efficient heterogeneous catalysts for the treatment of organic and inorganic contamination. Furthermore, the roles and performances of bimetallic catalysts in the removal of these environmental contaminants are different.


Assuntos
Eliminação de Resíduos Líquidos/métodos , Águas Residuárias/química , Catálise , Corantes , Poluentes Ambientais , Oxirredução , Poluentes Químicos da Água/análise
2.
Chemosphere ; 262: 128365, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33182124

RESUMO

The study of soil potentially toxic elements (PTE) contents and establishment of the geochemical characterization of areas which have never been studied is of great concern. In 2019, soil survey of the Armavir region (Armenia) was conducted in order to investigate the spatial pattern of PTE, reveal PTE geochemical associations and assess the origin-specific health risks. The application of compositional data analysis and geospatial mapping allowed to identify two clusters of samples. The first cluster was spatially located on volcanic rocks and was represented by Fe, Co, Mn, Ti, Zn, Ba, Pb suggesting a natural origin of PTE in these areas. The second cluster was allocated on the alluvial, deluvial, and proluvial sediments and represented by As, Cu, Cr, Ni. Such combination of elements in the same group indicates the anthropogenic introduction of some quantities of PTE. The latter is confirmed by the presence of outliers and extreme values for As, Cu and Ni, as well as by the spatial colocation of Fe, Mn, Co, Pb, Zn outliers and extreme contents. The health risk assessment showed that for children the multi-elemental non-carcinogenic risk was detected, while for the adults the non-carcinogenic risk and carcinogenic risk were below the allowable level. The detailed study of the risk levels showed that in first cluster comparatively higher risk were observed for Pb, V, Ba, Zn while in the second cluster: Fe, Co, Mn, As, Cr, Cu, Ni. The results indicated the necessity of additional in-depth studies with special focus on bioavailability of PTE.


Assuntos
Metais Pesados/análise , Poluentes do Solo/análise , Adulto , Armênia , Criança , Monitoramento Ambiental/métodos , Humanos , Medição de Risco , Solo/química
3.
Chemosphere ; 262: 128404, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33182127

RESUMO

BACKGROUND: Reduced growth velocity before birth increases the risk of adverse health outcomes in adult life. However, until recently, there has been a lack of studies demonstrating the impact of prenatal PM2.5 exposure on fetal growth velocity. METHODS: The current study was embedded in a previous cohort built between January 1, 2014, and April 30, 2015, in Shanghai First Maternity and Infant Hospital, China, in 6129 eligible singleton pregnancies. The PM2.5 concentration was estimated by an inverse distance weighted method according to the residential addresses of the participants. Repeated fetal biometry measurements, including head circumference (HC), abdominal circumference (AC), femur length (FL), and biparietal diameter (BPD), were measured through ultrasound between 14 and 41 gestational weeks. A principal component analysis through conditional expectation for sparse longitudinal data was used to estimate the corresponding velocities. RESULTS: A total of 22782 ultrasound measurements were conducted among 6129 participants with a median of 2 and a maximum of 9 measurements. With each 10 µg/m3 increase in cumulative PM2.5 exposure, the velocity of HC, AC FL and BPD decreased by 0.12 mm/week, 0.17 mm/week, 0.02 mm/week and 0.02 mm/week, respectively, on average. The results of the Generalized Functional Concurrent Model showed that the velocity decreased significantly with PM2.5 exposure between 22 and 32 gestational weeks, which might be the potential sensitive exposure window. CONCLUSIONS: There are negative associations between prenatal exposure to PM2.5 and fetal growth velocity, and the late second trimester and early third trimester might be the potential sensitive window.


Assuntos
Poluentes Atmosféricos/toxicidade , Exposição Materna , Material Particulado/toxicidade , Efeitos Tardios da Exposição Pré-Natal , Adulto , China , Estudos de Coortes , Feminino , Desenvolvimento Fetal , Idade Gestacional , Humanos , Masculino , Material Particulado/análise , Gravidez , Segundo Trimestre da Gravidez , Terceiro Trimestre da Gravidez , Ultrassonografia Pré-Natal/métodos
4.
Chemosphere ; 262: 128415, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33182128

RESUMO

The occurrence, fate and removal of microplastics (MPs) in a wastewater treatment plant (WWTP) in Central Italy were investigated together with their potential adverse effects on anaerobic processes. In the influent of the WWTP, 3.6 MPs.L-1 were detected that mostly comprised polyester fibers and particles in the shape of films, ranging 0.1-0.5 mm and made of polyethylene and polypropylene (PP). The full-scale conventional activated sludge scheme removed 86% of MPs, with the main reduction in the primary and secondary settling. MPs particles bigger than 1 mm were not detected in the final effluent and some loss of polymers types were observed. In comparison, the pilot-scale upflow granular anaerobic sludge blanket (UASB) + anaerobic membrane bioreactor (AnMBR) configuration achieved 94% MPs removal with the abatement of 87% of fibers and 100% of particles. The results highlighted an accumulation phenomenon of MPs in the sludge and suggested the need to further investigate the effects of MPs on anaerobic processes. Accordingly, PP-MPs at concentrations from 5 PP-MPs.gTS-1 to 50 PP-MPs.gTS-1 were spiked in the pilot-scale UASB reactor that was fed with real municipal wastewater, where up to 58% decrease in methanogenic activity was observed at the exposure of 50 PP-MPs.gTS-1. To the best of our knowledge, the presented results are the first to report of PP-MPs inhibition on anaerobic processes.


Assuntos
Eliminação de Resíduos Líquidos/métodos , Anaerobiose , Reatores Biológicos , Itália , Microplásticos , Plásticos , Polietileno , Esgotos , Águas Residuárias
5.
Chemosphere ; 262: 128385, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33182129

RESUMO

The study proposed the ultrasound-activated persulfate oxidation as a novel approach to enhance sludge dewaterability. The results demonstrated that the reduction of water content of dewatered sludge cake was 16.5% and the capillary suction time was reduced to 39.5 s at the optimal conditions of 1.0 mmol/g-TS S2O82- and ultrasound energy density of 2.0 kW L-1 within 15 min. The promotion of dewaterability was closely associated with the enlarged floc size, decreased viscosity, and near-neutral zeta potential. Meanwhile, the correlation analysis revealed that the protein in extracellular polymeric substances (EPS) governed sludge dewaterability, especially in loosely bound EPS. Three-dimensional excitation-emission matrix fluorescence spectroscopy, Fourier transform infrared spectroscopy and scanning electronic microscopy analysis revealed that ultrasound-activated persulfate oxidation treatment effectively degraded the gel-like EPS matrix and attacked cells, releasing the moisture which was trapped in EPS and cells. The aggregation of particles promoted the elimination of moisture. Furthermore, heavy metals in conditioned dewatered sludge cakes all satisfied the A level of agricultural land (GB4284-2018) requirements and the chemical speciation distribution of some heavy metals changed significantly.


Assuntos
Eliminação de Resíduos Líquidos/métodos , Matriz Extracelular de Substâncias Poliméricas , Oxirredução , Esgotos/química , Espectrometria de Fluorescência , Viscosidade , Água/química
6.
Chemosphere ; 262: 127930, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33182151

RESUMO

The beneficial recycling of drinking water treatment residue (DWTR) for environmental remediation has received increasingly interests; whereas, the reported potential effect of microbial communities in different DWTR was ambiguous, which was unfavorable for the beneficial recycling. This study hypothesized that the varied treatment to DWTR in different waterworks induced the ambiguous effect; accordingly, responses of microbial communities in DWTR to the sequential dewatering and drying treatment were determined based on samples from three waterworks, in combination with 180-d incubation tests. The results showed that the microbial communities varied remarkably in different DWTR before being dewatered (DWTS). However, after dewatering, the increased microbial diversities were observed, and the microbial communities exhibited higher similarities among the dewatered DWTR from different waterworks; furthermore, the dewatered DWTR with subsequent drying treatment enriched more bacteria genus with potential environmental functions after incubation tests. The variations of microbial communities were closely related to DWTR properties, such as pH, organic matter, metals, P, and water extractable nutrients. Further analysis indicated that with maintaining high adsorption capability of DWTR, the dewatering treatment tended to retain specific microbial communities that may be induced by the applied similar techniques in different waterworks; the accumulated nutriments due to drying treatment and the stable DWTR pH enhanced the potential functional bacteria enrichment. Overall, the dewatering and drying treatment led to microbial communities with generality in different DWTR and increased the potential favorable microbial effect, promoting DWTR recycling in environmental remediation.


Assuntos
Água Potável/química , Purificação da Água/métodos , Adsorção , Dessecação , Água Potável/análise , Recuperação e Remediação Ambiental , Metais , Microbiota , Reciclagem
7.
Chemosphere ; 262: 128390, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33182154

RESUMO

Hydroxylamine (HA) driven advanced oxidation processes (HAOPs) for water treatment have attracted extensive attention due to the acceleration of reactive intermediates generation and the improvement on the elimination effectiveness of target contaminants. In this review, HAOPs were categorized into three parts: (1) direct reaction of HA with oxidants (e.g., hydrogen peroxide (H2O2), peroxymonosulfate (PMS), ozone (O3), ferrate (Fe(VI)), periodate (IO4-)); (2) HA driven homogeneous Fenton/Fenton-like system (Fe(II)/peroxide/HA system, Cu(II)/O2/HA system, Cu(II)/peroxide/HA system, Ce(IV)/H2O2/HA system); (3) HA driven heterogeneous Fe/Cu-Fenton/Fenton-like system (iron-bearing material/peroxide/HA system, copper-bearing material/peroxide/HA system, bimetallic composite/peroxide/HA system). Degradation efficiency of the target pollutant, reactive intermediates, and effective pH range of various HAOPs were summarized. Further, corresponding reaction mechanism was elaborated. For the direct reaction of HA with oxidants, improvement of pollutants degradation was achieved through the generation of secondary reactive intermediates which had higher reactivity compared with the parent oxidant. For HA driven homogeneous and heterogeneous Fe/Cu-Fenton/Fenton-like system, improvement of pollutants degradation was achieved mainly via the acceleration of redox cycle of Fe(III)/Fe(II) or Cu(II)/Cu(I) and subsequent generation of reactive intermediates, which avoided the drawbacks of classical Fenton/Fenton-like system. In addition, HA driven homogeneous Fe/Cu-Fenton/Fenton-like system with heterogeneous counterpart were compared. Further, formation of oxidation products from HA in various HAOPs was summarized. Finally, the challenges and prospects in this field were discussed.


Assuntos
Hidroxilamina/química , Purificação da Água/métodos , Cobre , Compostos Férricos , Peróxido de Hidrogênio , Hidroxilaminas , Ferro , Oxidantes , Oxirredução , Peróxidos , Água , Poluentes Químicos da Água
8.
Talanta ; 222: 121534, 2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-33167242

RESUMO

As COVID-19 has reached pandemic status and the number of cases continues to grow, widespread availability of diagnostic testing is critical in helping identify and control the emergence of this rapidly spreading and serious illness. However, a lacking in making a quick reaction to the threat and starting early development of diagnostic sensing tools has had an important impact globally. In this regard, here we will review critically the current developed diagnostic tools in response to the COVID-19 pandemic and compare the different types through the discussion of their pros and cons such as nucleic acid detection tests (including PCR and CRISPR), antibody and protein-based diagnosis tests. In addition, potential technologies that are under development such as on-site diagnosis platforms, lateral flow, and portable PCR units are discussed. Data collection and epidemiological analysis could also be an interesting factor to incorporate with the emerging technologies especially with the wide access to smartphones. Lastly, a SWOT analysis and perspectives on how the development of novel sensory platforms should be treated by the different decision-makers are analyzed.


Assuntos
Técnicas de Laboratório Clínico/métodos , Infecções por Coronavirus/diagnóstico , Infecções por Coronavirus/epidemiologia , Pandemias , Pneumonia Viral/diagnóstico , Pneumonia Viral/epidemiologia , Técnicas de Laboratório Clínico/instrumentação , Humanos , Testes Imediatos , Kit de Reagentes para Diagnóstico
9.
Ann Med ; 53(1): 34-42, 2021 12.
Artigo em Inglês | MEDLINE | ID: mdl-32808808

RESUMO

BACKGROUND: Studies have demonstrated the diagnostic efficiency of antibody testing in COVID-19 infection. There is limited data on the IgM/IgG changes in asymptomatic and discharged patients with reoccurring positive nucleic acid test (RPNAT). This study aims to investigate these IgM/IgG changes. METHODS: There were 111 patients with positive nucleic acid test (NAT) and 40 suspected patients enrolled in the study. The serum SARS-CoV-2 specific IgM/IgG antibody levels were retrospectively analysed with the disease progress in asymptomatic and RPNAT patients. RESULTS: The best overall performance was found by combining the IgM, IgG, and CT; 95.1% sensitivity and 75% specificity. This was tested in 111 RT-PCR positive cases. The median IgM and IgG levels were lower in the asymptomatic group compared to the symptomatic group (p < .01). Among 15 RPNAT cases, the IgM levels of the RPNAT group at the time of discharge (IgM2.79, IQR: 0.95-5.37) and retest (IgM 2.35, IQR: 0.88-8.65) were significantly higher than those of the non-reoccurring positive nucleic acid test group (Non-RPNAT) (IgM on discharge: 0.59, IQR: 0.33-1.22, IgG on retest: 0.92, IQR: 0.51-1.58). CONCLUSION: Serum SARS-CoV-2 specific IgM/IgG antibody levels remained at a low level during hospitalisation for asymptomatic patients. Elevated IgM levels may have implications in the identification of RPNAT patients before discharge. Key messages This study determined the IgM/IgG changes in asymptomatic and RPNAT patients. The rate of serum SARS-CoV-2 specific IgM/IgG antibody levels increase in the asymptomatic group was lower than in the symptomatic group during hospitalisation. The IgM level did not decrease significantly at discharge in the RPNAT patients, and was higher than that of the Non-RPNAT group on discharge. These results highlight the importance of timely monitoring of IgM levels to identify RPNAT patients before discharge.


Assuntos
Anticorpos Antivirais/sangue , Betacoronavirus/isolamento & purificação , Infecções por Coronavirus/imunologia , Imunoglobulina G/sangue , Imunoglobulina M/sangue , Pneumonia Viral/imunologia , Estudos de Casos e Controles , Técnicas de Laboratório Clínico , Infecções por Coronavirus/diagnóstico , Feminino , Humanos , Técnicas Imunoenzimáticas/métodos , Masculino , Pandemias , Estudos Retrospectivos
10.
Clin Sports Med ; 40(1): 213-220, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33187611

RESUMO

As the COVID-19 (Coronavirus disease 2019) pandemic continues, the paradigm of treatment continues to rapidly evolve, especially for sports medicine surgeons, because treatment before the pandemic was considered predominantly elective. This article provides subjective and objective data on the changes implicated by the COVID-19 pandemic with regard to the interactions and practices of sports medicine surgeons. This perspective also considers the potential impact on the patients and athletes treated by sports medicine surgeons. This article discusses the impact of the COVID-19 pandemic on sports medicine and provides thoughts on how the landscape of the field may continue to change.


Assuntos
Betacoronavirus , Infecções por Coronavirus/epidemiologia , Procedimentos Ortopédicos/estatística & dados numéricos , Pandemias , Pneumonia Viral/epidemiologia , Medicina Esportiva/métodos , Cirurgiões/estatística & dados numéricos , Humanos
11.
J Infect Chemother ; 27(1): 117-119, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-32994136

RESUMO

The novel coronavirus disease 2019 (COVID-19) is diagnosed by positive result of reverse transcription polymerase chain reaction (RT-PCR) for the novel coronavirus. We concluded that cycle threshold value (Ct-value) of real-time RT-PCR (rRT-PCR) assay could decrease as patients recover. Results of rRT-PCR assay could remain positive among asymptomatic patients for longer than 2 weeks. The discharge criteria of COVID-19 patients using a negative result of rRT-PCR should be reconsidered.


Assuntos
Infecções por Coronavirus/diagnóstico , Pneumonia Viral/diagnóstico , Reação em Cadeia da Polimerase Via Transcriptase Reversa/métodos , Adolescente , Adulto , Idoso de 80 Anos ou mais , Doenças Assintomáticas , Betacoronavirus/isolamento & purificação , Técnicas de Laboratório Clínico/métodos , Infecções por Coronavirus/virologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Nasofaringe/virologia , Pandemias , Alta do Paciente , Pneumonia Viral/virologia , Índice de Gravidade de Doença , Carga Viral , Adulto Jovem
12.
J Infect Chemother ; 27(1): 126-129, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33060046

RESUMO

Considering the issues of shortage of medical resources and the invasiveness and infection risk involved in the collection of nasopharyngeal swab specimens, there is a need for an effective alternative test specimen for SARS-CoV-2 RNA detection. Here, we investigated suitability of saliva as a non-invasively obtained specimen for molecular detection of SARS-CoV-2 RNA in Japanese patients with COVID-19. In total, 28 paired clinical specimens of saliva and nasopharyngeal swabs were collected from 12 patients at various time points after symptom onset. Each specimen was assayed using reverse transcription real-time polymerase chain reaction (rRT-PCR) on the BD MAX open system using primers and probes targeting the N-gene. The saliva and nasopharyngeal swab specimens showed 19 and 15 positive results, respectively. No invalid (PCR inhibition) result was observed for any specimen. The qualitative results of each specimen obtained in the period immediately after symptom onset were similar. Three convalescent patients presented saliva-positive results, whereas their nasopharyngeal swabs were negative at four different time points, suggesting that saliva may be superior to nasopharyngeal swabs in terms of obtaining stable assay result of SARS-CoV-2. In conclusion, our results suggest that saliva can potentially serve as an alternative to nasopharyngeal swabs as a specimen for SARS-CoV-2 rRT-PCR. As saliva can be collected by patients themselves, it may be an effective way to overcome the shortage of personal protective equipment and specimen sampling tools.


Assuntos
Betacoronavirus/isolamento & purificação , Infecções por Coronavirus/diagnóstico , Nasofaringe/virologia , Pneumonia Viral/diagnóstico , RNA Viral/isolamento & purificação , Saliva/virologia , Técnicas de Laboratório Clínico , Humanos , Japão , Pandemias , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Manejo de Espécimes/métodos
13.
Food Chem ; 334: 127605, 2021 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-32738726

RESUMO

Chitosan (Ch) and zinc oxide nanoparticles loaded gallic-acid films, (Ch-ZnO@gal) have been prepared aiming for their exploitation as environmentally benign food packaging material. The chitosan films with varying quantities of zinc oxide nanoparticles loaded gallic-acid (ZnO@gal) content were synthesized in order to evaluate the effect of ZnO@gal on their optimum mechanical and biological potential. The characteristic results have shown that the incorporation of ZnO@gal into chitosan films remarkably enhanced the desired mechanical property of the chitosan films. Other noticeable physical properties such as oxygen and water vapor permeability (WVP), swelling, water solubility and UV-vis light transmittance have also been found to improve positively. SEM analysis of the films indicates a good material compatibility between chitosan and ZnO@gal matrices. Ch-ZnO@gal films possess significant antibacterial potential and strong antioxidant behavior compared to pristine chitosan. The overall results suggested that the prepared biocomposite chitosan films may be considered for active food packaging applications.


Assuntos
Quitosana/química , Embalagem de Alimentos/métodos , Ácido Gálico/química , Nanopartículas/química , Óxido de Zinco/química , Antibacterianos/química , Antioxidantes/química , Bacillus subtilis/efeitos dos fármacos , Materiais Biocompatíveis/química , Escherichia coli/efeitos dos fármacos , Embalagem de Alimentos/instrumentação , Permeabilidade , Solubilidade , Vapor , Resistência à Tração , Raios Ultravioleta , Óxido de Zinco/farmacologia
14.
Food Chem ; 334: 127563, 2021 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-32791433

RESUMO

A new magnetic Cu(II) IIP (Fe3O4@IIP-IDC) is synthesized by polymerization of Imidazole-4,5-dicarboxylic acid functionalized Allyl chloride, and significant improvement of its performance has been compared. SPE parameters were optimized using Box-Behnken design to achieve the twin objectives of quantitative determination and removal of Cu(II). FLPSO kinetic model and BS isotherm model fits well with the capacity of 175 mg g-1. Analytical figures of merit includes a linearity range of 10-5,000 µg L-1 (R2 = 0.9986), preconcentration factor of 50 after eluting with 5 mL of 1 M HNO3, LOD of 1.03 µg L-1 and LOQ of 4.5 µg L-1. Accuracy was assessed by analysis of SRM (Standard Reference Material) and recovery experiments after spiking in food samples (Tea, coffee, chocolate, spinach, infant milk substitute) and battery wastewater. Ease of use, reusability (15 cycles), rapid adsorption and high selectivity makes it a promising candidate for efficient and selective removal and trace determination.


Assuntos
Cobre/análise , Análise de Alimentos/métodos , Impressão Molecular/métodos , Polímeros/química , Poluentes Químicos da Água/análise , Adsorção , Compostos Alílicos/química , Cobre/isolamento & purificação , Ácidos Dicarboxílicos/química , Análise de Alimentos/instrumentação , Contaminação de Alimentos/análise , Imidazóis/química , Limite de Detecção , Fenômenos Magnéticos , Águas Residuárias/análise , Poluentes Químicos da Água/isolamento & purificação
15.
Food Chem ; 334: 127471, 2021 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-32688174

RESUMO

Optimal QuEChERS (quick, easy, cheap, effective, rugged and safe) conditions with good accuracy, repeatability and precision were established to rapidly extract the European Union (EU) priority polycyclic aromatic hydrocarbons (PAHs) from various food matrices (Category: Poultry and Meat, Fish and seafood, Grains, Soy beans and products, Root vegetables and Coffee). The QuEChERS conditions combined with the established high performance liquid chromatography-fluorescence detection conditions were used to rapidly determine the PAHs in 19 popular cooked foods in Taiwan and their corresponding original materials. These conditions also meet the EU and Taiwan Food and Drug Administration specifications. Charcoal grilled, gas stove grilled and smoked foods had higher PAHs contents, while fried and electric oven-baked/baked foods had lower PAHs contents. In addition to the effects of cooking methods, the contamination of original materials by PAHs in the environment should also have an important impact on the contents of PAHs in these cooked foods.


Assuntos
Análise de Alimentos/métodos , Contaminação de Alimentos/análise , Hidrocarbonetos Policíclicos Aromáticos/análise , Carvão Vegetal , Fracionamento Químico/métodos , Cromatografia Líquida de Alta Pressão , Culinária , União Europeia , Cromatografia Gasosa-Espectrometria de Massas/métodos , Limite de Detecção , Carne/análise , Reprodutibilidade dos Testes , Alimentos Marinhos/análise , Taiwan , Verduras/química
16.
Food Chem ; 334: 127474, 2021 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-32688175

RESUMO

Rapid and accurate detection of pesticide residues in food matrices are of great significance to food safety. This study aimed to characterize the fingerprint peaks of 2,4-dichlorophenoxyacetic acid (2,4-D) and to enhance its detection accuracy in food matrices by using terahertz (THz) time-domain spectroscopy. Density functional theory was used to simulate molecular dynamics of 2,4-D peaks (1.35, 1.60, 2.37 and 3.00 THz). Four baseline correction methods, including asymmetric least squares smoothing (AsLS), adaptive iteratively reweighted penalized least squares (AirPLS), background correction (Backcor), baseline estimation and denoising with sparsity (BEADS) were compared and used to eliminate spectral baselines of Zizania latifolia (ZIZLA), rice and maize containing 2,4-D residues, from 0.1 to 4 THz. Based on the peak information of 1.35 THz, the detection limit and accuracy of 2,4-D residues in these food matrices were significantly improved after THz spectral baseline correction, providing a new feasibility for food safety and agricultural applications.


Assuntos
Ácido 2,4-Diclorofenoxiacético/análise , Resíduos de Praguicidas/análise , Espectroscopia Terahertz/métodos , Análise de Alimentos/métodos , Análise de Alimentos/estatística & dados numéricos , Contaminação de Alimentos/análise , Inocuidade dos Alimentos , Análise dos Mínimos Quadrados , Simulação de Dinâmica Molecular , Oryza/química , Espectroscopia Terahertz/estatística & dados numéricos , Zea mays/química
17.
Food Chem ; 334: 127436, 2021 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-32711262

RESUMO

Milk samples (150 cow and 217 camel milk samples) were analyzed for protein, fat, lactose and total solids by near and mid-infrared transmission spectroscopy. Excellent positive correlations between the two methods were obtained for both types of milk (p < 0.001); for protein (r ≥ 0.96), fat (r ≥ 0.99), lactose (r = 0.82) and total solids (r = 0.90). The mean of the relative difference ((MIR values - NIR values)/0.5 (MIR values + NIR values) × 100%) for cow and camel milk were, for protein (+8.2 & +13.4%), fat (-9.3 & +0.9%), lactose (-5.4 &-0.7%) and total solids (-2.2 &-3.4%), respectively. The difference between the two methods may be due to the effects of differences in milk homogeneity, especially with respect to casein micelles and fat globules.


Assuntos
Análise de Alimentos/métodos , Lactose/análise , Proteínas do Leite/análise , Leite/química , Espectrofotometria Infravermelho/métodos , Animais , Calibragem , Camelus , Caseínas/análise , Bovinos , Gorduras na Dieta/análise , Feminino , Reprodutibilidade dos Testes
18.
Food Chem ; 334: 127345, 2021 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-32712485

RESUMO

The development of a novel molecularly imprinted solid-phase extraction (MISPE) method for simultaneous preconcentration of imazapyr (IMP), imazapic (IMZ) and imazethapyr (IMT) with determination by HPLC-PAD (High performance liquid chromatography - photodiode-array detector) is proposed. The polymer synthesis was performed using imazethapyr as template molecule and 1-vinylimidazole as functional monomer. The method is based on preconcentration of 100.0 mL of sample through 200.0 mg of molecularly imprinted poly(vinylimidazole-TRIM) (MIP-1VN) at pH 4.0, followed by elution with 2.0 mL of MeOH:CH2Cl2:HAc (34:62:4, v/v). The range of analytical curve (0.29-200.0, 0.21-200.0 and 0.15-200.0 µg L-1), limits of detection (0.09, 0.06 and 0.04 µg L-1) and preconcentration factors (92, 96 and 98) determined for the herbicides, IMP, IMZ and IMT, respectively, were greatly superior when compared with those ones obtained with commercial adsorbents. The analytical method was successfully applied to spiked surface water and rice samples with good results of recovery values (86-107%).


Assuntos
Herbicidas/análise , Impressão Molecular/métodos , Oryza/química , Extração em Fase Sólida/métodos , Poluentes Químicos da Água/análise , Cromatografia Líquida de Alta Pressão/métodos , Contaminação de Alimentos/análise , Imidazóis/análise , Imidazóis/síntese química , Imidazóis/química , Limite de Detecção , Niacina/análogos & derivados , Niacina/análise , Ácidos Nicotínicos/análise , Ácidos Nicotínicos/química , Polivinil/síntese química , Polivinil/química , Sementes/química , Extração em Fase Sólida/instrumentação
19.
Acta Pharm ; 71(2): 163-174, 2021 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-33151166

RESUMO

The current outbreak of novel coronavirus (COVID-19) infections urges the need to identify potential therapeutic agents. Therefore, the repurposing of FDA-approved drugs against today's diseases involves the use of de-risked compounds with potentially lower costs and shorter development timelines. In this study, the recently resolved X-ray crystallographic structure of COVID-19 main protease (Mpro) was used to generate a pharmacophore model and to conduct a docking study to capture antiviral drugs as new promising COVID-19 main protease inhibitors. The developed pharmacophore successfully captured five FDA-approved antiviral drugs (lopinavir, remdesivir, ritonavir, saquinavir and raltegravir). The five drugs were successfully docked into the binding site of COVID-19 Mpro and showed several specific binding interactions that were comparable to those tying the co-crystallized inhibitor X77 inside the binding site of COVID-19 Mpro. Three of the captured drugs namely, remdesivir, lopinavir and ritonavir, were reported to have promising results in COVID-19 treatment and therefore increases the confidence in our results. Our findings suggest an additional possible mechanism of action for remdesivir as an antiviral drug inhibiting COVID-19 Mpro. Additionally, a combination of structure-based pharmacophore modeling with a docking study is expected to facilitate the discovery of novel COVID-19 Mpro inhibitors.


Assuntos
Infecções por Coronavirus/enzimologia , Pneumonia Viral/enzimologia , Inibidores de Proteases/farmacologia , Monofosfato de Adenosina/análogos & derivados , Monofosfato de Adenosina/química , Monofosfato de Adenosina/farmacologia , Monofosfato de Adenosina/uso terapêutico , Alanina/análogos & derivados , Alanina/química , Alanina/farmacologia , Alanina/uso terapêutico , Antivirais/química , Antivirais/farmacologia , Infecções por Coronavirus/tratamento farmacológico , Cristalografia por Raios X , Descoberta de Drogas/métodos , Reposicionamento de Medicamentos , Humanos , Modelos Químicos , Simulação de Acoplamento Molecular , Estrutura Molecular , Pandemias , Pneumonia Viral/tratamento farmacológico , Inibidores de Proteases/química , Relação Estrutura-Atividade
20.
Food Chem ; 337: 127768, 2021 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-32889326

RESUMO

A stability-indicating HPLC-DAD method for simultaneous determination of all nine main water-soluble vitamins, in addition to two commonly used vitamers, was developed and fully validated in analytical ranges, adjusted to their recommended dietary allowance values. An XSelect CSH C18 column with gradient elution using phosphate buffer and methanol was used for their optimal separation. The results from forced degradation studies along with peak purity tests and response ratios at dual wavelengths for the individual vitamins in all tested samples confirmed the method's stability-indicative nature. The complete developed methodology, including a single sample preparation for the vitamins simultaneous analysis, was applied to their assay in 13 commercial multivitamin preparations, revealing mostly higher amounts than the label claims. The developed method is applicable for stability testing, multivitamin products shelf-life determination as well as routine assay analysis of all water-soluble vitamins in their most common forms, including the analytically most demanding flavin mononucleotide.


Assuntos
Cromatografia Líquida de Alta Pressão/métodos , Vitaminas/análise , Cromatografia Líquida de Alta Pressão/normas , Suplementos Nutricionais/análise , Limite de Detecção , Controle de Qualidade , Comprimidos/química , Vitaminas/isolamento & purificação , Vitaminas/normas
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA